\documentclass{standalone}
\usepackage{tikz,ctex}
\usetikzlibrary{patterns}
\begin{document}
\footnotesize
  \begin{tikzpicture}[>=stealth,scale=0.5]
    \draw[thick](0,0)--++(0,1.6)arc(180:90:1.0)--++(2.5,0)--++(1.2,-1.2)--++(0,-1.4)--cycle;
    \foreach \x in {1.0,2.0,3.0} 
      {
        \draw[thick] (\x,1.6)circle(0.3);
        \draw[thin](\x,2.0)--(\x,3.1);
      }
    \draw[thin,->]([shift=(210:0.5)]2.0,1.6)--++(30:0.2);
    \draw[thin]([shift=(210:0.3)]2.0,1.6)--++(30:0.6);
    \draw[thin,<-]([shift=(30:0.3)]2.0,1.6)--++(30:0.4)node[midway,sloped,above]{$d$};
    \draw[thin,<->](1.0,2.9)--(2.0,2.9)node[midway,sloped,above]{$s$};
    \draw[thin,<->](2.0,2.9)--(3.0,2.9)node[midway,sloped,above]{$s$};
    \draw[thin](3,1.6)--++(-30:0.7)node[below]{销孔};
    \draw[thin] (3.6,2.6)--(5.5,2.6);
    \draw[thin] (4.8,0)--(5.5,0);
    \draw[thin,<->](5.4,0)--(5.4,2.6)node[midway,sloped,above]{$B$};
    \draw[thin] (0,-0.1)--(0,-0.8);
    \draw[thin] (4.7,-0.1)--(4.7,-0.8);
    \draw[thin,<->](0,-0.7)--(4.7,-0.7)node[midway,sloped,above]{$L$};
  \end{tikzpicture}
\end{document}